OPTION2: 3riflemen->liutenant->m20 (judge if he is close to the p2, this depends on how well you are playing the early game) then if he ISNT close ->ambulance->captain->stuart->BARs , if he is close then ->captain->stuart->ambulance->BARs
OPTION1: 4 riflemen->Captain->BARs or ambulance -> Stuart -> Bar or ambulance depending on the one you didnt do (judge if your squads have low HPs)
OPTION2: 3 riflemen->liutenant->m20->Ambulance->BARs (perfect scenario where early agression was enough to delay the 222 to some extent)
OPTION3: 3riflemen->liutenant->ambulance->BARs->HMG (hmg might not be needed, you can always tech straight up to captain it depends on the fuel, in this scenario you are pretty much investing in what would go into the m20 into an early ambulance for squad healing and BARs for stronger infantry play.
Grenades in all these scenarios are up to how the game is going, how many munitions you have to spend, what is the build order of the opponent (if he is building many MGs) , for me the grenades either come at the same time as the ambulance or after the stuart is out. Hope this was clear enough.
Yeah, thanks for taking the time to write all that.